Orthogonal frequency division multiple access (Orthogonal Frequency Division Multiple Access, hereinafter referred to as OFDMA) becomes system key multiple access of a 3G system and/or a 4G system, and is a downlink multiple access technology used in a Long Term Evolution (Long Term Evolution, hereinafter referred to as LTE)/Long Term Evolution-Advanced (LTE-Advanced, hereinafter referred to as LTE-A) system. In terms of time, one radio frame is 10 ms in length, including 10 subframes; each subframe is 1 ms in length, and each subframe includes two timeslots, where each timeslot includes seven (in a case of normal cyclic prefix (Cyclic Prefix, hereinafter referred to as CP)) or six (in a case of extended CP) orthogonal frequency division multiple (Orthogonal Frequency Division Multiple, hereinafter referred to as OFDM) symbols. In terms of frequency, the radio frame is formed by multiple subcarriers, where one subcarrier corresponding to one OFDM symbol is referred to as one resource element (Resource Element, hereinafter referred to as RE). Twelve subcarriers and one timeslot form one resource block (Resource Block, hereinafter referred to as RB). A resource block is classified into a physical resource block (Physical Resource Block, hereinafter referred to as PRB) and a virtual resource block (Virtual Resource Block, hereinafter referred to as VRB). A PRB indicates a location of an actual frequency of a resource block, and a VRB is a form of a renumbered PRB, that is, information is mapped to the PRB by using the VRB. System information required by a terminal is transmitted on these time-frequency resources. The system information includes public information of a serving cell or multiple cells; and the public information is transmitted by using a master information block (Master Information Block, hereinafter referred to as MIB) or a system information block (System Information Block, hereinafter referred to as SIB), where SIBs may be system information blocks that are of different types and are used to transmit different public information, for example, a SIB 1, a SIB 2, and a SIB 3, and all these SIBs are system information.
In the prior art, a MIB is borne on a physical broadcast channel (Physical Broadcast Channel, hereinafter referred to as PBCH) for transmission, and a SIB is borne on a physical downlink shared channel (Physical Downlink Shared Channel, hereinafter referred to as PDSCH) for transmission. Generally, when system information needs to be transmitted, a SIB in a subframe where a physical downlink control channel (Physical Downlink Control Channel, hereinafter referred to as PDCCH) locates, is scheduled by using a public search area of the PDCCH, that is, a cyclic redundancy check (Cyclic Redundancy Check, hereinafter referred to as CRC) code of the PDCCH is scrambled by using a system information radio network temporary identity (System Information Ratio Network temporary Identity, hereinafter referred to as SI-RNTI), which indicates that a PDSCH scheduled by the PDCCH is used to transmit the system information; meanwhile, the PDCCH indicates, by using downlink control information, resource block allocation information and a modulation and coding mode of a PDSCH that corresponds to the system information, so as to transmit the system information by using the PDSCH, where the resource allocation information indicates a time-frequency resource of the PDSCH that corresponds to the system information, and a maximum of the time-frequency resource may reach an total downlink system bandwidth.
It can be learned that in the prior art, when system information needs to be transmitted, a PDCCH needs to use downlink control information to schedule a PDSCH corresponding to the system information; however, a control instruction of the PDCCH causes an extra overhead, and an overhead of the PDCCH is relatively large. Therefore, a waste of the control instruction of the PDCCH may be caused in the prior art.